THE DROSOPHILA-MONTIUM SUBGROUP SPECIES - PHYLOGENETIC-RELATIONSHIPS BASED ON MITOCHONDRIAL-DNA ANALYSIS

Mitochondrial DNA (mtDNA) restriction site maps for three Drosophila m ontium subgroup species of the melanogaster species group, inhabiting Indian and Afrotropical montium subgroup territories, were established . Taking into account previous mtDNA data concerning six oriental mont ium species, a phylogeny was established using distance-matrix and par simony methods. Both genetic diversity and mtDNA size variations were found to be very narrow, suggesting close phylogenetic relationships a mong all montium species studied. The phylogenetic trees that were con structed revealed three main lineages for the montium subgroup species studied: one consisting of the Afrotropical species Drosophila seguyi , which is placed distantly from the other species, one comprising the north-oriental (Palearctic) species, and one comprising the southwest ern (south-oriental, Australasian, Indian, and Afrotropical) species. The combination of the mtDNA data presented here with data from other species belonging to the melanogaster and obscura subgroups revealed t wo major clusters: melanogaster and obscura. The melanogaster cluster is further divided into two compact lineages, comprising the montium s ubgroup species and the melanogaster complex species; the species of t he other complex of the melanogaster subgroup, yakuba, disperse among the obscura species. The above grouping is in agreement with the mtDNA size variations of the species. Overall, among all subgroups studied, the species of the montium subgroup seem to be the most closely relat ed.